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I've moved your thread from Mercury Mappers to Q&A; I think it will get more of a response there.

As far as your question... I think there are several reasons. One is that Mercury and Venus are much more difficult to visit. It is much harder to get a rocket to Mercury and the atmosphere of Venus is very corrosive. Even the few unmanned probes that have been sent there don't survive long.

Mars is also interesting because it is the most likely of the three to have had life, or at least at one time had life.

I've moved your thread from Mercury Mappers to Q&A; I think it will get more of a response there.

As far as your question... [removed] I think there are several reasons. One is that Mercury and Venus are much more difficult to visit. It is much harder to get a rocket to Mercury and the atmosphere of Venus is very corrosive. Even the few unmanned probes that have been sent there don't survive long.

Mars is also interesting because it is the most likely of the three to have had life, or at least at one time had life.

I agree with most of what Swift wrote, but there's one point I don't agree with, namely the notion that out of the other three terrestial planets, Mars is the most likely one to have harboured life at some point in the solar system's history. My reason for disagreeing on this point is that the Sun was a lot cooler at the genisis of the solar system and has since gotten progressively hotter; it is estimated that the Sun is 30% hotter, today, than it was when it formed four and a half billion years ago. Venus almost certainly had oceans in the past when the Sun was cooler than it is today, although it's still up for debate at which point Venus lost its oceans, with some models suggesting it was a billion or so years after the formation of the solar system, while others suggest this happened as recently as 750 million years ago. Given that Venus is almost comparable to Earth in size and mass, and has been much more geologically active than Mars - it probably still is, as a transient hot spot was observed in the vicinity of Maat Mons, by one of the spacecraft we put into orbit around Venus, and it was probably caused by the effusion of lava - it is much more likely that the kind of water and rock interactions that we think gave rise to life on Earth also happened on Venus. Tricky thing about Venus, though, is that it appears it experienced a period of global volcanism that pretty much resurfaced the whole planet about 500 million years ago, which makes finding traces of ancient life trickier than it would be if it existed on Mars. The Venusian highlands appear to date before this period of volcanic activity, though, and could potentially hide traces of ancient Venusian life.

Finding out if there are fossils of Venusian dinosaurs burried in the Venusian highlands would be way more of a challenge seeing as Venus, much like Mercury, is an insanely hot environment, not to mention the pressure of its atmosphere, which does not make matters any easier. It is for the same reason sending men and/or women to Venus is not an attractive proposition, at least not with our current technology. If Mars isn't friendly to macroscopic life such as ourselves, Venus is outright hostile, and the same can be said for Mercury, although, funnily enough considering Mercury is closer to the Sun than Venus, Mercury is not as hot as Venus. This is because of Venus's thick atmosphere which acts like a greenhouse and traps heat. There's no atmosphere on Mercury, though, which means that any rocket landing there with humans would have to bring much more fuel to be able to propulsively land there, and once you're there, there wouldn't be any protection whatsoever against the solar wind and cosmic rays. While Venus does not have much by the way of a magnetic field, its thick atmosphere picks up some of the harmful particles that make up the solar wind or cosmic rays.

While Mars is the best option as far as our next pitch stop in the solar system goes, if we're gonna get a little bit spacey and far seeing, I believe Venus is a much more attractive proposition when it comes to settling another world permanently. We wouldn't have to worry about the low gravity of Mars and the effects it would have on human health, and it already has a substantial atmosphere, so if it weren't for the hot temperatures, water could exist in liquid form there. To cool down Venus, we could shield it off from the heat of the Sun with a giant shade and thereby lower the temperature of the planet to the point where the co2 that makes up almost all of its atmosphere would freeze out. We'd probably like to keep some co2 in the atmosphere, though, as without it the planet would be too chilly and water wouldn't be able to exist in liquid form.

____________"Dumb all over, a little ugly on the side." -- Frank Zappa"Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson"This is really very simple, but unfortunately it's very complicated." -- publiusModerator comments in this color | Get moderator attention using the lower left icon:
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I'm afraid it's even worse: he did not even care about the question, as he stole it verbatim from a reddit page.

____________"Dumb all over, a little ugly on the side." -- Frank Zappa"Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson"This is really very simple, but unfortunately it's very complicated." -- publiusModerator comments in this color | Get moderator attention using the lower left icon:
Recommended reading:Forum Rules * Forum FAQs * Conspiracy Theory Advice * Alternate Theory Advocates Advice